Presented By Rajarshi Ghose Dastidar Roll no 149 Why do we need them It is known that VoltageV of a power supply system must be maintained at a constant value Other wise the performance of any motormachinery will drop considerably ID: 600261
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Slide1
Automatic Voltage Regulator
Presented By:
Rajarshi
Ghose
Dastidar
.
Roll no. 149Slide2
Why do we need them????
It is known that Voltage(V) of a power supply system must be maintained at a constant value.
Other wise the performance of any motor/machinery will drop considerably.
When any new load is given to an un-regulated AC Generator, the V drop is more substantialSlide3
Close control of generator voltage is required to prevent such dips in V
.
This control is achieved by an Automatic Voltage Regulator
(AVR)The real need of the AVR is to deal with the voltage dip following the sudden connection of extra load and to restore the rated Voltage without undue overshooting and regeneration(i.e.
voltage hunting)Slide4
There are two stages that follow when the extra load is connected. Transient Stage(followed by recovery)
Steady state condition
time
VSlide5
How does it work?
There are three basic parts to an AVR:
Error detecting element
Correcting ElementStabilizing ElementSlide6
Block DiagramSlide7
The AVR senses
the
DC
output voltage and acts to alter the field current to maintain the output voltage at its set valueThe excitation voltage can be set by the hand trimmerThe VOLTAGE SENSING unit transforms down, rectifies and smoothes the generator output voltage. This produces DC signal proportional to the actual generator voltage.
This signal is compared with the set value at the COMPARATOR
The ‘error’ signal from the Comparator is used to control the excitation current through ERROR AMP. and CONTROLLER.Slide8Slide9